Liam Gallagher has promised his Beatles film will be "mega".The Beady Eye rocker is working on a movie about the British musical legends, and although he hasn't cast anyone or secured rights to use the group's music, he thinks fans will enjoy the biopic.He said: "It's not started yet but it's going to be mega. Script's finished, we're just waiting to tie things up with Apple to see if we can use some of their tunes. And then we'll be able to see what kind of actors we want to get. But it's gonna happen, definitely, next year."